With the advent of digital radio the FCC has mandated In Band-on-Channel (IBOC) which is a hybrid analog-digital transmission system mode. FM stations in the U.S., based on the IBOC requirements, will be able to simultaneously broadcast FM-based analog and digital signals within their current allocated frequency range. Due to current FCC regulations, DA 03-831, OMB Control No. 3060-1034, issued Mar. 20, 2003, IBOC systems, separate antenna elements for analog and digital signal transmission is not permitted. Broadcast stations must use a dual input antenna that combines both the analog and digital signals within the same frequency channel while maintaining isolation between the signals.
The only current published solution to this requirement is discussed in the IEEE Broadcast Technology Society-Digital Radio Tutorial, published Oct. 9, 2002, the contents of which are incorporated herein by reference in its entirety. The IEEE dual-input antenna is conceded as generally being an expensive solution for small markets or sites that are not multiplexed.
Accordingly, a new system or method for transmitting iBiquity IBOC signals using a single antenna system is desired in the broadcast community.